<textarea id="editor">
	<objectfoo data-foo="bar">objectfoo</objectfoo>
	<embedfoo data-foo="bar">embedfoo</embedfoo>
	<paramfoo data-foo="bar">paramfoo</paramfoo>
	<htmlfoo data-foo="bar">htmlfoo</htmlfoo>
	<headfoo data-foo="bar">headfoo</headfoo>
	<bodyfoo data-foo="bar">bodyfoo</bodyfoo>
	<titlefoo data-foo="bar">titlefoo</titlefoo>
</textarea>

<script>
	var elements = [
			'object',
			'embed',
			'param',
			'html',
			'head',
			'body',
			'title'
		];

	CKEDITOR.replace( 'editor', {
		extraAllowedContent: elements.join( 'foo[*]{*}(*);' ) + 'foo[*]{*}(*);',
		autoParagraph: false
	} );
</script>
